/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.gaia.translation.functions;



import com.bff.gaia.unified.sdk.transforms.join.RawUnionValue;

import com.bff.gaia.unified.sdk.util.WindowedValue;

import com.bff.gaia.api.common.functions.FlatMapFunction;

import com.bff.gaia.util.Collector;



/**

 * A {@link FlatMapFunction} function that filters out those elements that don't belong in this

 * output. We need this to implement MultiOutput ParDo functions in combination with {@link

 * GaiaDoFnFunction}.

 */

public class GaiaMultiOutputPruningFunction<T>

    implements FlatMapFunction<WindowedValue<RawUnionValue>, WindowedValue<T>> {



  private final int ourOutputTag;



  public GaiaMultiOutputPruningFunction(int ourOutputTag) {

    this.ourOutputTag = ourOutputTag;

  }



  @Override

  @SuppressWarnings("unchecked")

  public void flatMap(

      WindowedValue<RawUnionValue> windowedValue, Collector<WindowedValue<T>> collector)

      throws Exception {

    int unionTag = windowedValue.getValue().getUnionTag();

    if (unionTag == ourOutputTag) {

      collector.collect(

          (WindowedValue<T>) windowedValue.withValue(windowedValue.getValue().getValue()));

    }

  }

}